How To Introduce Your Horse to Grass

By Jennifer Rice, DVM on Oct. 27, 2023

Benefits of Pasture Grazing

Pasture grazing is extremely beneficial not only because it’s the way a horse's digestive tract was meant to intake and ingest food, but also because it is mentally stimulating and a great exercise for your horse.

Feeding a horse today can be tricky due to the fact a horse's digestive tract is constantly producing gastric acid (whether they are eating or not). This natural constant production of gastric acid into the stomach occurs because they are meant to be continually grazing.

When a horse is not eating, the gastric acid can build up in the stomach. By grazing in the pasture, horses are able to “use” the acid that is produced in their stomach and decrease the risk of this acid leading to gastric ulcers. Besides the gastric acid, horses are less likely to colic if they are able to continually take in smaller portions of food instead of larger meals as we often feed them today.

Living in stalls can be mentally stressful for horses. Allowing them time outside to be free to graze has been shown to not only help with boredom and unwanted behaviors, but also decrease the risk of gastric ulcers due to stress.

Grazing also provides a horse with exercise. Horses in the wild may graze for up to 17 hours a day, walking over 5 miles a day. Not only is this exercise good for any horse, but is especially good for senior horses that may have arthritis.

While any type of turnout (dirt lot and sand) can be a good mental break for any horse, if appropriate and safe, pasture turnout can be extremely beneficial both mentally and physically even for short durations.

How Long Does It Take for a Horse to Get Used to Grass?

Just like with introducing any new food item to a horse, grass should be introduced slowly and gradually increased over a few weeks. The length of time it takes to introduce grass will depend on the horse’s medical health, pasture quality, and current diet.

If your horse has had no grass introduction, then it may be best to start with hand grazing for 15–20 minutes at a time for 3–5 days.
Increase the total time horses are on pasture by 15–30 minutes every 3–4 days depending on the time of year and your individual horse's needs.
Once they are up to 3–4 hours per day, keep horses grazing at this length of time for 1–2 weeks before giving them the total desired daily turnout time.

If you do not have access to a stall then try to start your horse in a smaller paddock with less grass and use a grazing muzzle as needed to limit the horse's grass intake initially.

If your horse has been in a stall with no turnout or pasture, follow the above instructions for pasture turnout. You may also want to exercise your horse ahead of being turned out. This will help prevent them from being over excited and potentially hurting themselves when they run around on the grass. You may also consider smaller turnout areas first for their safety.

Unfortunately, domesticated horses today may have medical conditions that make grazing on grass potentially harmful to their health. Depending on the disease, these horses may be able to graze on grass in limited amounts, with grazing muzzles, or not at all. Some of these conditions include:

Spring vs. Fall Grass

Spring grass can pose an increased risk to horses, especially with those that have sensitivities. Due to the temperatures becoming warmer, spring grass has an enhanced ability to photosynthesize (produce sugars and grow).

This same risk also occurs in the fall, when the days are still sunny, and nights begin to cool. During these seasons the sugar in the grass is at its highest for the year. If you want to let your horse out during the fall and spring but are concerned about the sugar in the grass, the best time to turn your horse out is early in the morning between 3 a.m. and 10 a.m., when the sugar is at its lowest.

During spring and fall, always take precautions and slowly increase a horse’s pasture turnout or start using a grazing muzzle to lessen the amount of grass a horse is able to eat. If a horse already uses a grazing muzzle, this may be a good time to replace the current muzzle with a new one (as the hole generally wears and becomes bigger over time). This will decrease the amount of grass but not take away the pasture turnout time.

If you have a horse that has a medical condition that makes him sensitive to sugar in the grass, then it is best to discuss turnout with your veterinarian to come up with an individualized plan to keep your horse safe.

Are Horses Happier in Pasture?

The benefits of horses having time outside in their natural setting are irrefutable. Horses that have pasture turnout tend to show fewer behavioral issues, lowered risk of digestive diseases such as gastric ulcers and are able to manage respiratory illness such as Recurrent Airway obstruction easier.

In addition, horses are social animals and meant to live in groups or herds, so turnout time where they can see or be with other horses can be even more beneficial to the well-being of your horse.

Can Horses Graze on Freshly Mowed Pasture?

Horses should never be fed grass clippings from a typical lawn as these pose an increased risk of many serious medical conditions including colic, choke, and founder.

Grass clippings are often more lush than pasture clippings and likely going through a fermentation process. While they may taste good to your horse, your horse may also try to eat them too quickly causing them to choke.

Colic and founder are alternative risks to lawn clippings as they can drastically upset the balance of microbes in the hindgut and hold high amounts of highly fermentable carbohydrates.

A horse can, however, be put in a pasture that has been mowed as these are often different clippings than a lawn. If you have a horse that is prone to laminitis or colic, then you can mow the pasture, wait one day to allow the cut grass to dry out, and then turn your horse out the following day.

In general, it is recommended to have 2–4 acres of pasture per horse if you intend for the horse to be grazing 24 hours per day. Less acreage is needed if you intend for the horse to be in the pasture for less hours per day.

Additionally, being able to rotate pastures is best in order to prevent overgrazing and parasite management. A pasture should be left to recover when the grass is 3–4 inches long, and it may take several weeks to recover. Horses may be placed back on the pasture to graze when the grass has reached 8 inches.

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